Telephone system



` -Dea 24, 1929. T. F. cRocKr-:R

TELEPHONE SYSTEM Filed April 2e. 1927 Im Y Thnmas' Bracket' Patented Dec. 24, 1929 UNETE,

TATES THOMAS E'. CRGCKER, OF CHICAGO, ILLINOIS, ASSITOR TO RESERVE HOLDING COM- PANY, OF KANSAS CITY, MISSOURI, A CORORATION OF DELAWARE TELEPHONE SYSTEM Application filed April 28, 182'?.

This invention relates to telephone systems in general, but is more particularly concerned with auxiliary equipment by which calls over one or a group of telephone lines may be answered and supervised from a common position.

ln business otiices and the like, it is often desirable to employ some scheme whereby calls to one or a number of telephones may be answered from one position, a stenographers desk or an attendants desk, for example, so that if the person called is not in his oliice at the time or is too busy to answer the call, the

stenographer or attendant may answer the call. The object of this invention is the production of new and improved circuit arrangements for such a position whereby calls over one or a group of telephone lines may be answered Vand supervised.

The main feature of this invention is the extreme simplicity of the circuit arrangements, and these, with other features not specifically mentioned, and the operation thereof will be described in detail with the aid of the accompanying drawing, which discloses the invention by means of the usual schematic circuit diagrams, and illustrates sufiicient of an automatic telephone system in which it may be employed so that the invention may be easily understood and its utility appreciated.

Referring to the drawing, the apparatus between the two dotted vertical lines is located at the attendants desk. The lines which the attendant is to supervise are accessible in the banks of connectors at the automatic switchboard and also terminate thereat in individual line switches. In the drawing, the line of substation A comprising conductors 2 and 3, which is accessible in the banks of the connectors such as connector C and which terminates in the lineswitch LS, is one of these lines. At the attendants desk, for each one of these lines there is provided a key such as key K by which the attendant may connect her telephone set G to any one of the lines, a key such as key K2 for use in supervising a connection, two supervisory lamps such as lamp L and L2, and two relays for controlling the signalling and supervisory circuits.

Serial No. 187,223.

A line for the attendants private use may also be provided, and such is shown in the drawing comprising conductors 2 and 3. This line is also provided with keys, lamps, and relays having substantially the same function as the keys, lamps, and relays of the other line shown, but differing in some details as will be described later.

Besides the attendants telephone set, previously mentioned, there is also a buzzer B at this position for apprising the attendant of all incoming calls.

The substations of the telephone lines such as substation A shown are of the usual automatic type well known in the art. The attendants telephone set may be of the same type as the substation A with the ringer removed.

The lineswitches LS and LS may be of any suitable type, such as the well known rotary type; and the connectors C and C may also be of any suitable type such as the well known Strowger vertical and rotary type. The other switches of the exchange are not shown, since they do not concern this invention.

lVth this general description of the apparatus in mind, a detailed description of the operation may now be given. For this purpose it will first be assumed that a call is extended to the line of substation A by way of the connector C. The connector C, after this line has been connected with, connects ground potential to the release conductor 4 and applies ringing current intermittently to the conductors 2 and 3 in the usual manner. Ringing relay 5 responds to this ringing current and in operating closes the circuit of relay 6 at contacts 7. Relay 6 operates and closes a circuit for the buzzer B at contacts 8, and closes a circuit for the lamp L2 at contacts l0. At contacts 11, relay 6 short circuits the condenser l2, thereby placing a di rect current bridge across the line conductors 2 and 3. This permits a ilow of direct current through ringing relay 5 in series with the ring-cut-oif relay (not shown) in the connector C during the silent period. Therefore relay 5 is held operated during the silent period,

and as a result, relay 6 is maintained energized continuously during the intermittent application of ringing current to the line. The resistance of relay 5 plus the resistance R, however, is sufficiently high to limit the direct current ilow through the ring-cut-off relay in the connector C to prevent its operation. The intermittent application of ringing current to the line conductors 2 and 3 also causes the bells at substation A to ring in the usual manner.

lf the called party is in his oiiice, which fact the attendant at the desk will in all probability know, she `will disregard the lamp signal and the sounding of the buzzer forthe time being. iV hen the called party removes his receiver toia'nsw'e'r the call, relay 5 will be short-circuited by reason of the bridge placed acfoss'the line conductors 2 Yand 3 at the vsubstation A. Relay 5 thereupon releases iits armature and opens the circuit 'of 'relay 6. `ltelay then releases its armature andopens thecircuitofthe buzzer B at contacts 8 and opensthe circuitof the lamp L2 atcontacts 10. rlhus, thebuzze'r B is stopped sounding and the "lamp L2 iis extinguished and the attendant is informed that the called party has answered. Further details of the connection'are omitted'since' they donot concern this Einvention.

Shouldthe called party not be in 'his office at the' time: this connection is extended, which fact the attendant will'most vprobably know, she will operate the key K and remove'her receiver from her `telephone set as soon as she is apprised of lthe incoming call, (or she ma-y-'dothis-after the'buzzer has sounded are'asonablel'ength of time to assure her that the calledlpartyfisnot inhis office'rv at the time,

or'istoo busy-'to answer). l/Vhen the attendant removes :her receiver and'operat-es the key K, the attendants telephone set'is connectedaerossithefline conductors 2 and 3 by the closur'eof contacts 15and 16 which has the same 'eliiect concerning the connection as hougl'i the called party had removed his receiver. Thus, :relay 5 is again short circuited, which yon releasing its armature causesrelay G to=release- The buzzer stops sounding and thelamp'L2 is extinguished as previously' described. @perating the vkey K also closes contacts 17 thereby closing'acircuit for lamp L1. The lighting of the lamp L1 indicates tothe-attendant that her telephone 'set is associated with this particular line `at this time.

The attendant may now converse with-'the calling subscriber andinform him ofthe' absence ofthc personwith whom he wishes to `converse or-'gii'e him such other information as the circumstances dictate. Ifthe calling subscriber then replaceshisreceiver, the attendantmay yrestore thefkey K and replace herf re'Ceivver'therebyv releasing'the connection and restoring the apparatusto normal;

In orderrto describe alparticular feature of this invention, it will be assumed that the calling subscriber is particularly anxious to speak with the desired person if it be possible, in which case the attendant will inform the calling subscriber that she will attempt to locate the person with whom he4 wishes to converse, if he wishes to wait on the line. Assuming that this procedure is chosen, the attendant will operate the key K2 and restore the key K1 to disconnect her telephone set from this line, and then take such steps as necessary to locate the desired person, after which she may proceed to answer other calls. Throwing the key K2 and restoring the key K1 closes circuitsfor both lamps L1 and L2 1 ich extend from ground on the release conductor lthrough contacts 18 closed by the operation of key K2, the circuit for lamp L1 also including` contacts 9 and 19. The

lighting of these two lamps now indicates to the attendant that the calling subscriber is waiting onthis line. Y

lf the desired person is located and he comes to the telephone, he may remove'the yreceiver and commence conversation with the calling subscriber. ldlhen the conversationis finished, both subscribers will replace their receivers. This initiates the release of the connection and the automatic switches associated therewith inthe usual manner, ground potential being removed from the release conductor il. The removalvof ground from'the release conductor l'opens the circuit-of the lamp L1 and L2, thus causing` vthese lamps to be extinguished. rlhe extinguishing of these lamps indicates tothe attendant that this connection has beenreleased, whereupon she will restore the key K2.

Should the vcalling subscriber become iinpatient while waiting for the desired person 2 i to be located and replace his receiver, again the connection would be releasedand ground removed from the conductor 4 causing extinguishment of the lamps L1 and L2. :If another call were now extended to the line conductors 2 and S while the key Y2 were operated, relay 5 and relay 6 would again operate, the buzzer B would be sounded and the light L2 would again be lighted, just as though the key K2 were not operated. Lamp L remains dark since its circuit is held open by the separation of contacts 9. The calledparty or the attendant, if'the called party were not aresent, could again answer the call in the usual manner.

The attendant may makeoutgoing calls over herprivate linecomprising conductors 2 anc 3 and may also answer calls extended over this line in substantiallyithe same way as in answering a call over one of the other lines. The lighting` of the lamp L12 when connection to this lineis made indicates to her that the call is for her personally. She will therefore throw the' key vK11 `and remove her receiver as soon as-the buzzer B sounds and the lamp L12 lights and commence conversation. To make an outgoing call, the attendant removes her receiver and operates the key K, and then dials in the usual manner.

The key K12 has a particular function that the corresponding keys of the other lines do not have. Its lower springs are arranged to throw a direct bridv'e across the line conductors when the key K12 is operated. To describe the particular function of this key for this line it will be assumed that the attendant has made an outgoing call and is holding conversation with some subscriber and that during this time a call comes in over one of the other lines which requires her ttention. She may then operate the key K12 and hold this connection intact by virtue of the bridge across the conductors 2 and 3 at contacts 20', and then by releasing the talking key K11 and operating the talking key for the line which requires attention, she may connect her telephone set with this other line. After she has given the other line the required attention she may again reconnect her telephone set with her individual line by throwing the key K11 and releasing the corresponding key of the other trunk line, and then restore the key K12. Thus the attendant is able to temporarily disassociate her telephone set from one line and associate it with another, without releasing the first connection. As in the previous case, both lamps L11 and L12 light when the key K12 is operated, in this case indicating to the attendant that she is holding up a connection on her private line. If the attendant is called over her private line, she may likewise momentarily interrupt her conversation and give attention to another call. She may in this case also operate the key K12 while she is answering the other call, although of course the release of the connection is controlled by the calling party. The lighting` of the two lamps L11 and L12, however keep her reminded that she has left a connection over her own line.

This completes the description of this invention. What is thought to be new and is desired to have protected by Letters Patent is specilically pointed out in the appended claims.

lVhat is claimed is:

l. In a. telephone svstem, a line terminating in a lineswitch and accessible in the banks of connectors, said line comprising' talking conductors and a release conductor, a ringing relay for said line controlled over the talking conductors, and a signal for said line controlled over the release conductor.

2. In a telephone system, an individual subscribers line, an attendants switchboard, means for extending a connection to said line and for automatically signalling the subscriber at the station, a signal thereon for opprising the attendant at the switchboard of the incoming call, a telephone set at said switchboard, means whereby the attendant may connect said telephone set to said line and answer the callin the event that the called subscriber does not answer the call, and a second signal operable after the attendant has answered the call, in case she does answer it, for apprising the attendant when the connection is released.

3. In a telephone system, individual subscribers lines, and attendants switchboard, means for extending a connection to any one of said lines and signalling the subscriber at the station thereon, a signal individual to each line for apprising the attendant the particular line being called, a telephone set, means whereby the attendant may temporarily associate said telephone set with any line called and answer the call in the event that the called subscriber does not answer the call, and a second signal operable after the attendant has answered the call, in case she has answered it, for apprising the attendant when the connection is released.

4. In a telephone system, a plurality of individual subscribers telephone lines, each line having a station thereon, and means at one of the stations for apprising t-he subscribr thereat when ever a call has been extended to any one of said lines.

5. In a telephone system, a plurality of individual subscribers telephone lines, each line having a station thereon, means at one of the stations for apprising the subscriber thereat whenever a call has been extended to any one of said lines, and means at said one of the stations for apprising the subscriber thereat to which line the call has been extended.

6. In a telephone system, a plurality of individual subscribers telephone lines, each line having a station thereon, means at one of the stations for apprising the subscriber thereat whenever a call has been extended to any one of said lines, means at said one of the stations for apprising the subscriber thereat to which line the call has been extended, and means at said one of the stations for associating the telephone set of that stat-ion with the line to which the call has been extended.

7. In a telephone system, a plurality of individual subscribers telephone lines, each line having a station thereon, means at one of the stations for apprising the subscriber thereat whenever a call has been extended to any one of said lines, means at said one of the stations for apprising the subscriber thereat to which line the call has been extended, means at said one of the stations for associating the telephone set of that station with the line to which the call has been extended, and means at said one of the stations for apprising the subscriber thereat when the call is terminated.

8. In a telephone system, a plurality of subscribers7 telephone lines, veach kline extendingfrom anexchangeto a subscribers station, a telephone sety at one of the stations, and keys Wherebysaid telephone set lmay at any time'be'connected toany one of said telephone lines.

9. In atelephone system, a subscribersline, a kstation thereon, aV branch of said line, a second station on said branch, ar signal at said iirst station periodically responsive to the intermittent application of ringing potential to said line, a signal at said second station,vand means atvsaid second station responsive to the intermittent application of ringing potential to said line for operating said second signal continuously.

10. In a telephone system, a subscribers line, a sta-tion thereon, a branch of said line, a-second station-on said branch, a signal at said irst station periodically responsive to the intermittent` application of ringing` potentialzto said linefto apprise the subscriber at' said iirst station of an incoming call, a signal at -said second station, and inea-ns at said second station actuated responsive to the intermittent application ot' ringing potential to said line .for continuously actuating said lsecond signal to apprise the subscriber atsaid second station ofthe incoming' call, andL deactuated responsive to the removal of the receiverV at the-first station to-deactuate said second signal to apprise the subscriber atY said second station that the call has been answered.

11. In a telephonesystem, a group -of subscribers stations, aline for each sta-tionconnectingfthe station with an eXchange,.an attendantsline extending `from said exchange to an attendantsstation Whichis on the same premises With. said group of stations, a branch of each subscribersline extending to the attendants station, and'akeyboard at the attendants station comprising` keys by means of which the attendants `telephone may be disconnected trom her line and may be connected instead to any one of said branches to answer a call. p

12; In a telephonersystem in which the signalen a called line is operated by the intermittent application of a source of alternating lcurrent potential to the called line andlin which-a source of direct current potential is applied to the line during the silent periods, a line, a' first relay and a condenser connected'in series across the conductors of said line, said relay being responsive initially to currentfrom said first source only, a second relay controlled by said first relay, and means controlled by said second relay for short-circuiting said condenser, said relay being thereafter responsive to-current from eithernv source. Y

j13.,In a telephone-system in which the signal on a called line is operated'by the intermittent application ofa sourcey of alternating current potential vto the called line and in Which a'source of directycurrent potential is applied to the line during the silent periods, a line, a tirst relay and a condenser connected in series across the conductors of said line, said relay being` responsive initially to vcurrent from said iirst source only, a second relay controlled bysaid lirst relay, means controlled by said second relay for shortcircuiting said c-ondenser, said relay being thereafter responsive to current from either source, and a signal operated continuously under the control of said second relay during the intermittent application of alternating current to the called line.

1l. In a telephone system, a line comprising` talking conductors and a release conductor, a signal-control relay for the line controlled over the talking conductors, and a signal for-the line controlled by said relay under certain conditions and controlled over the release conductor under certain other` conditions.

l5. In a telephone system, a line comprising talking conductors and a release conductor, a signal-control relay for the line contr lied over the talking conductors,- a signal normally controlled by-said relay, and a key for causing the signal to be controlled over the release conductor.

In Witness whereof, I hereunto subscribe my name this 23rd day of April, A. D.. 1927.

THGMAS F. CROCKER. 

